Learn more about Markham's Flood Control & Stormwater
Learn more about Markham's Flood Control/Stormwater Projects.
Don Mills Channel Flood Reduction
Notice of Commencement
A Notice of Commencement for the project was issued on July 27, 2018 and August 2, 2018 in the Markham Economist & Sun.
Background
As part of Markham’s Flood Control Program, a Class Environmental Assessment was initiated on the Don Mills Channel.
The Don Mills Channel is a small man made channel that runs through the commercial / industrial area in the Woodbine Ave and Denison Street area. Several of the private properties and roads in this area are prone to flooding during large storm events.
The environmental assessment aims to:
- Identify and understand the causes of flooding in the study area
- Develop a range of alternative solutions to reduce flooding and flood damages from the Don Mills Channel
- Recommend the preferred solution or suite of solutions to best reduce flooding and flood damage
- Establish the funding, approvals and other activities needed to implement the recommended solutions.
The Study Objective is to provide flood protection for a Council Approved 5 year Level of Protection for the Don Mills Channel Area, as per the following Council Resolution (February 2013):
That the City's flood control strategy adopt a 5 year level of service target for Don Mills Channel drainage system based on its original design and consider other options, subject to technical feasibility and approval as part of a future Class EA;
The current system of open channels and culverts does not have adequate capacity to handle storm water runoff during large storm events. Businesses surrounding the Don Mills Channel have flooded numerous times since the land was developed in the 1970’s. Major roads in the study area, including Woodbine Avenue, can be impassable during severe storms.
The Don Mills Channel study area was realigned and confined to a relatively narrow channel corridor through urban development. Significant portions of the Don Mills Channel were also piped through some of the older development sites in the study area.
Study Area
Download a high resolution PDF of the study area
Estimated Flooding
This image shows the predicted extents of flooding from the August 19, 2005 storm event within the study area, and pictures taken during and shortly after the storm.
Project Schedule
- Winter / Spring 2016
- Notice of Study Commencement
- Existing Conditions Inventory and Analysis
- Fall 2016
- Liaison committee meeting with key stakeholders to review existing conditions
- Public Information Centre (PIC) #1
- Spring / Summer 2017
- Development of initial flood reduction alternatives
- City / Agency Technical Consultation Process
- Spring 2018
- Liaison committee meeting with key stakeholders to review preliminary preferred alternative
- Public Information Centre #2
- Summer 2018
- Confirmation or Refinement of Preferred Alternative
- Finalize the Project File Report, post the Notice of Completion and make the final report available for 30 day public review period
Evaluation
The evaluation is based on the following criteria:
Natural Environment
- Potential impact on terrestrial system (vegetation, trees and wildlife)
- Potential impact on aquatic systems (aquatic life, surface water and groundwater)
- Potential to improve natural environmental conditions
Social Environment
- Disruption to existing community during construction (business disturbance, traffic, noise)
- Impacts to community in the long term (emergency access, land acquisition, aesthetics)
- Ability to reduce risks to public safety
- Impacts to Archaeological systems and First Nations
- Timeless of implementation
Technical
- Effectiveness of solution in reducing flood risk (minimum 5 year level of service target)
- Impacts on upstream and downstream landowners
- Long term operations and maintenance
- Ability to meet regulatory requirements
Economic
- Estimated costs to implement project
- Estimated costs of long term operations and maintenance
- Reduction in potential future flood damages
- Estimated losses in tax revenue
Preliminary Preferred Alternative
The preliminary evaluation of the options identified as part of the EA process can be found on the Evaluation of Alternatives Table.
On February 20, 2018, City staff presented the preliminary preferred alternative depicted below to Council, and received approval to hold public meetings to receive feedback on this alternative. A public meeting will be held on April 4, 2018 to obtain feedback from the public on the evaluation that has been performed by the City and TMIG in recommending this as the Preliminary Preferred Alternative through the Environmental Assessment process.
Documents, News & Resources
Process for Project Municipal Class Environmental Assessment
Class EA Phase 1
Identify Problem or Opportunity
- Identify Need
- Initiate Consultation with the public and agencies
- Notice of Commencement
Background Review
- Obtain and review background documentation and initiate agency contact
- Identify data gaps to be address during the site inventory/ investigation
Class EA Phase 2
Site Inventory / Investigation
- Undertake natural heritage investigations
- Aquatic habitat assessment
- Incidental wildlife survey
- Undertake hydrology/hydraulics investigation
- Archealogical Investigattions
- Identify opportunities and constraints
- PIC #1
Evaluation of Alternatives
- Identify alternatives
- Complete impact assessments
- Evaluate alternatives
- Select preferred alternative
- Preliminary Design / Project File Report
Preliminary Design / Project File Report
- Preliminary design of preferred alternative
- Recommendation for further study, if required
- PIC# 2
- Develop a staging and implementation plan
- Prepare Project File Report
- Notice of Completion
- 30-day Public Review
Implementation
- Detailed Design / Implementation
- Detailed design of the proposed works
- Obtain permits and approvals
- Prepare contract drawings and tender documents
- Construction and operation of the worksPost-construction monitoring
Project ifnormation about the Class EA Process for Municipal Infrastructure Projects.
Get Involved
You can get involved in the planning process by attending public information meetings which will take place throughout the process. Sign up for our email list by contacting one of the managers below to stay informed throughout the project.
Contact
Robert Grech, P.Eng.,
City Project Manager, City of Markham
8100 Warden Avenue
Markham, Ontario, L6G 1B4
905.477.7000 extension 2357
rgrech@markham.ca
This multi-phase program will reduce the risk of basement flooding. It will also limit environmental concerns caused by directly connecting downspouts to the sanitary sewer system. These connections increase the flow of rainwater into the sanitary sewer system during heavy or long rain events. This can cause:
- The sanitary sewer system to overflow
- Sanitary sewer backups
- Basement flooding
This program also enforces the existing City of Markham Sewer By-Law # 2014-71 [PDF] [Clauses 3.1D & 19.11]. It also enforces the Region of York’s Sewage and Land Drainage By-Law # S-0064-2005-009, which prohibits the discharge of roof drainage water into the sanitary sewer system.
This program will be done in five phases, but this is subject to change.
Phase 1 Program Area
The first phase of the program began in May, 2013 within the Thornhill area. The investigations and testing work within the Phase 1 Area [PDF] was finished in April 2014. The downspout disconnection work has been finished. Flow monitoring within the area started in Spring/Summer 2016.
Phase 2 Program Area
The second phase of the program began in May, 2014 within the Thornhill Area. The investigation and testing work with Phase 2 Area [PDF] was finished in April 2015. The notice of disconnection was mailed out to affected homeowners in June, 2015. The downspout disconnection work has been finished. Flow monitoring within the area commenced in Spring 2017.
Phase 3 Program Area
The third phase of the program began in May, 2015. It covered areas within Thornhill, Milliken, and Unionville. The investigation and testing work within the Phase 3 Area [PDF] ended in April, 2016. The downspout disconnection work has been finished.
Phase 4 Program Area
The fourth phase of the program began in May, 2016 within the Markham Area. The investigations and testing work within the Phase 4 Area [PDF] ended in February 2017. The notice of disconnection was mailed out to affected homeowners in September 2017.
Phase 5 Program Area
The fifth phase of the program began in May 2017, which covers area within Thornhill and Unionville. The investigation and testing work within the Phase 5 Area [PDF] was completed in November 2017. The notice of disconnection will be mailed out to the affected homeowners in Fall 2018 and the disconnection period will end in Fall 2019. Post condition flow monitoring within the area will commence in Spring/Summer 2020.
Phase 5 Expansion Program Area
The fifth phase expansion of the program began in September 2017, which covers area within Thornhill and Markham Village. The investigation and testing work within the Phase 5 Expansion Area [PDF] has been starting since November 2017.
Phase 6 Program Area
The sixth phase of the program began in September 2017, which covers areas within Unionville and Markham Village. The investigation and testing work within the Phase 6 Area [PDF] will commence in June 2018.
Steps taken by City to identify downspout discharge locations
Before any downspouts are disconnected, the City needs to confirm whether the downspouts that go into the ground are actually connected to the municipal sanitary sewer system. To do this, the City takes following steps:
- Preliminary property investigation
We do general surveys of residential lots to see whether downspouts are discharging above the ground or into the ground.
- Sanitary & storm sewer smoke testing
We do smoke testing within the sanitary and storm sewer systems. This involves blowing a non-toxic, highly visible smoke through the systems and observing the exit points of the smoke. This test finds whether downspouts that go into the ground are connected into the sanitary sewer system or the storm sewer system. The smoke test also identifies other devices/equipment that are connected to the underground sewer system.
Identified downspouts that discharge into the municipal sanitary sewer system
After the investigations and testing are finished, the City will send a Notice of Disconnection to homes with downspouts connected to the sanitary sewer system. The notice will tell you which downspouts within your property need to be disconnected. We will send you more information about how to disconnect a downspout and use rain barrels when the downspout disconnection stage starts.
Financial Assistance Plan
Markham Council has approved a Financial Assistance Plan for the Sanitary System Downspout Disconnection Program. This will help homeowners with the cost to disconnect downspouts from the sanitary sewer.
Only homeowners who receive a disconnection notice from the City will be eligible.
- The City will reimburse 80% of the cost for completing the downspout disconnection, up to a maximum of $500;
- The City will reimburse 100% of the cost for a rain barrel purchased by the home owner, up to a maximum of $150.
Ask for Partial Cost Reimbursement
You can ask for part of your costs to be paid by the city. Follow these steps:
- Fill out the Financial Assistance Application Form [PDF] and send it to the City. Include all original/photocopy receipts by mail, e-mail, or fax. Please write "Downspout Disconnect - Financial Assistance Application" in your submission.
- Once the City receives your application package, City staff will contact you to inspect the disconnected downspouts.
- Once the City sees that the downspouts have been disconnected properly, we will process your application and send you a cheque.
How to disconnect a downspout
- Ensure there is a suitable area for the water to discharge from the downspout
- Ensure downspouts are disconnected and drained properly away from the foundation walls and directly to a storage device (e.g. a rain barrel), your lawn, or garden.
- When disconnecting downspouts, remember not to drain directly onto neighbouring properties, lanes, or sidewalks.
- Extend your downspout to discharge water at least 1 metre from any structure's foundation (including your neighbour’s) or public sidewalk, and 2.5 metres from retaining walls.
- Ensure the ground slopes away from the house for a minimum of 1 metre.
- Use a splash pad to help direct the flow of water and protect against erosion.
- Ensure eavestroughs are clean and drain properly.
- Obtain professional advice and service from a knowledgeable and licensed roofer, eavestrough contractor, or civil engineer.
Read this Step-by-step procedure to disconnect your downspouts [PDF]
Using Rain Barrels
Rain barrels collect rainwater from downspouts and rooftops. They decrease the amount of storm water runoff that leaves your property. A rain barrel collects water and stores it for those times that you need it most. Using rain barrels can help you lower your water bill and improve your lawns, plants, flowers, and trees.
Rain barrels are easy to install and provide relatively clean water for non-drinking purposes. Here are some tips:
- Install a splash pad with the rain barrel. Put it under the barrel’s tap and overflow spout to direct roof water away from your home’s foundation walls.
- Install the rain barrel on a strong, level surface. It can weigh up to 1200 pounds when full! A patio or paving stone is best.
- If the rain barrel is slightly elevated, attach a hose to direct water towards a garden or lawn via gravity.
- To limit mosquito-breeding, ensure that your rain barrel is mosquito/vector proof. Most manufactured rain barrels come with this feature.
- Drain your rain barrel before each storm event. This will let it fill up when it rains, and will stop it from cracking in the winter.
Helpful Links
Contact Us
Help is only a phone call away! Waterworks staff will be more than happy to help you. Please call us at 905.477.5530.
Why Does West Thornhill Need a Stormwater Flood Remediation Plan?
On August 19, 2005, the West Thornhill community was impacted by a severe rain storm during which stormwater runoff exceeded the capacity of drainage systems, causing extensive flooding of private property and roadways.
The West Thornhill Stormwater Flood Remediation Class EA Study identified system improvements to increase capacity and reduce flood risks and received Ministry of the Environment approval in August 2011.
An implementation strategy was adopted in October 2011 that defined phases of design and construction projects throughout the community based on flood risk priorities. West Thornhill Flood Control is a consistent with principles of Markham’s asset management plan for stormwater infrastructure, including meeting desired level of service related to flood risk mitigation.
Learn more about the Class EA, implementation strategy and the status of ongoing projects:
- Class Environmental Assessment Report (2010)
- Implementation Strategy (2011 to 2013)
- Implementation Areas and Construction Dates
- Phase 1 (design complete, construction 2014 to 2016)
- Phase 2 (detailed design ongoing, construction 2016 to 2018)
- Phase 3 (detailed design ongoing)
- Phase 4 (detailed design ongoing)
Latest News
The existing conditions system review is underway. If you have any questions, or would like to provide any information on the drainage system, please contact one of the project managers (information below).
Background
As part of Markham’s Flood Control Program, the City will be initiating a study to investigate flooding associated with drainage systems in Markham Village and Unionville. The Markham Village area experienced considerable flooding during the July 2017 storm events.
The current storm sewer system does not have adequate capacity to handle stormwater runoff during large storm events. For the most part, the area was designed and constructed prior to 1978 when the City began requiring drainage system be designed for the 100 year storm event.
When the storm sewer system capacity is exceeded, flooding of basements, roads and properties is possible in this area.
The study aims to:
- Identify and understand the causes of flooding in the study area
- Develop a range of alternative solutions to reduce flooding and flood damages
- Recommend the preferred solution or suite of solutions to best reduce flooding and flood damage
- Establish the funding, approvals and other activities needed to implement the recommended solutions.
Once the study is completed, an implementation plan and prioritization strategy will need to be developed to define a timeline for design and construction of the mitigation works.
Project Schedule
April 2018 – February 2019
- Study Commencement
- Existing Conditions Inventory and Analysis
January 2019 – May 2019
- Evaluation of Flood Control Alternatives
May 2019
Summer 2019
- Preliminary Preferred Solutions to be Identified
- Agency/Internal Consultation
- Implementation Planning
November 2019
December 2019
- Confirmation or Refinement of Preferred Solutions based on Public Consultation
Documents, News & Resources
Get Involved
You can get involved in the planning process by attending public information meetings, which will take place throughout the process. Sign up for our email list by contacting our project manager below to stay informed throughout the project.
Contact
Robert Grech, P.Eng.,
City Project Manager, City of Markham
8100 Warden Avenue
Markham, Ontario, L6G 1B4
905.477.7000 extension 2357
rgrech@markham.ca
Ken G. Collicott, P.Eng.
Consulting Project Manager, RV Anderson Associates Ltd.
2001 Sheppard Avenue East, Suite 300
Toronto, Ontario, M2J 0A1
416.497.8600 extension 1294
kcollicott@rvanderson.com
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